Map markers

Release 0.0.1 (v10):

- Map: a map file can be exported, with all edited layers, in a simple lua table. Each map table contains the name, width, height, and string data of every layer associated.

- Markers: simple way to add information to a map. all markers all exported in the final map file

Too much bugfixes were corriged, can't list them all (see git)